Anderson Cooper sat down with Beyoncé hours before the star took the stage on August 10 at the United Nations General Assembly Hall to sing for an audience that included a mix of celebrities and other invited guests.

The crowd watched her perform "I Was Here” from her album “4,” released in 2011. The lyrics express a desire to make an impact in the lives of others: “The hearts I have touched will be the proof that I leave, that I made a difference and this world will see, I was here.”

Anderson asked Beyoncé about the song, which she is dedicating to the recognition of World Humanitarian Day. “It says, ‘I want to leave my footprints in the sands of time’ and it basically is all of our dreams, I think. And that’s leaving our mark on the world. I feel like we all want to know that our life meant something,” she explained. It’s a message she hopes will resonate and inspire acts of kindness around the world.

The show will be used as a music video released on August 19 to mark World Humanitarian Day. The U.N.’s website for the campaign is asking people to add their voice as part of a social media effort to raise awareness. There are also suggestions of how to “do something good somewhere for someone else.”

“We all have our purpose, and we all have our strengths...it feels so wonderful to do something for someone else. And I think for the U.N. to want to include the whole world was something important, and I feel like that’s what I represent,” Beyoncé told Anderson.

During the interview, Anderson also spoke with U.N. under-secretary-general and emergency relief coordinator Valerie Amos about their goal of reaching one billion people, and partnering with Beyoncé. “This is really about saying to everyone out there that this is a day that’s both a commemoration because there are a lot of people who lose their lives trying to help people. But it’s also a celebration of the things that people do,” Amos said.

Watch a preview of their conversation to find out why Beyoncé was attracted to the project, and see the full interview tonight at 8 and 10 p.m. ET on CNN.